Forging furnace



Mar. 13; 1923.

. H. o. B AKER FoRGiNG FURNACE Filed Jul 5-1,;1919 2 sheets-sheet 1 I M02507", Harry afireaker I v B} (Mew/11mm Mar; 13, 1923.

H. o. BREAKER FORGING F RNACE Filed July 51, 1919 2 sheets-shet 2 jwe zfofi, Harv Qfireakar Patented Mar. 13, 1923.

'IES

HARRY O. BREAKER, OF WINTHROP, MASSACHUSETTS, ASSIGNOR TO INDUSTRIAL,

FURNACE CORPORATION, OF BOSTON, MASSACHUSETTS; A CORPORATION OF MASSA- CHUSETTS.

FOlEtG-ING FURNACE.

Application filed July 31, 1919. Serial No. 315L535.

To allwhom it may concern:

Be it known that I, HARRY O. BREAKER, a citizen of the United States, and a resident of Winthrop, Suffolk County, Massachusetts, have invented certain new and useful Improvements in Forging Furnaces, of which the following is a full and complete specification.

My invention relates to a furnace adapted particularly for annealing sections of bar stock for forging and the like. Ordinarily such furnaces are operated to direct a flame at a very high temperature on the part to be heated. This results in checking the surface of the part to be heatedancl also demands that the operator watch the forging carefully to remove it from the heat when it looks hot enough. The question of whether or not the pro-per temperature has been reached depends on the skill of the operator.

I have discovered that if heat concentrations;

are properly controlled so that the heat may be delivered to the stock quickly but at a temperature not in excess of that to which it is desired to heat the forging, the factor of the skill of the operator can be largely eliminated. To accomplish the best results the forging is first exposed to a heat lower than that to which it is ultimately to be raised and gradually exposed to increasing degrees of heat.

To accomplish this result I provide a combustion chamber in which combustion can be largely completed before the flame strikes the forging. I also provide large masses of brick work surrounding this com-v bustion chamber which are adapted to absorb the heat generated therein and deliver it quickly to the part to be heated; in other words I so control the con centrationof the heat that I have a large volume of heat not substantially above the temperature ultimatelydesired, instead of having a high concentration of heat relatively small in volume but high in temperature. I also provide means for measuring the temperature of the working chamber or hearth at its hottest point, and further provide means for changing the heat concentration at the hearth without changing the amount of'combustion. This is desirable, for with a given combustion I can either heat a small section of stock to a high temperature or a larger section of stock to a lower temperature. A specimen furnace embodying my invention is shown in the accompanylng drawings 1n which:

Fig. I 1s a cross section of line II of cover or upper brick work removed and one portion broken away and Fig. III is a section On line III-III of Fig. I.

As shown in the drawings the furnace is provided with an oil burner 2 as an initial source of combustion. Burner 2 opens: into a combustion chamber 3 which extends the length of the furnace and which is of sufficient size so that combustion may be largely completed therein. Surrounding the combustion chamber 3 at the bottom and two sides is a mass of brick work l. Other simi lar brick work 5 is placed above the combustion chamber 3. The brick work 5 is not attached to brick work 4, but is adapted to be moved so that an opening 6 of desired size may be left between the two parts thereof, through which the products of combustion may escape and direct heat may pass to forgings that rest on the brick work 5. The movement of the brick Work 5 is controlled by the metal casings 7 in which the brick work 5 is clamped, and the arms 8 which are mounted on shafts 9. Brick work 5 is also divided transversely intoseparate units as shown in Fig. III. The relative position of such units can be changed if desired. However this will not ordinarily be necessary.

Above the brick work 5 is similar brick work 10 which serves as a cover for the hearth. This brick work is similar to the brick work 5 and is held in similar casings 11. Between the parts of brick work 10 is an opening 12 which may be adjusted in size like opening 6, though in this case the rocker arms are not necessary.

When the furnace is started, the brick work 4 and 5 will absorb large quantities of heat and owing to the blast of the oil burner there will be less: heat near the burner than at the very end. In order to measure the temperature at the hottest point a thermo-.couple 13 enclosed in a metal casing is placed on the brick work 5 at the end of the furnace farthest from the burner 2. This thermo-couple is connected to a pyrometer 14: of usual construction. It will be noted that the thermo-couple is housed in a suitable false forging of a material similar to that of the forgings to be heated. It will Fig. III. Fig. II is a plan view with the accordingly be evident that as the temperature of the forgings increases, they will ap proach in color the color of the false forging and accordingly a relatively accurate check on the temperature of the forgings may be kept. By reason of the open sides of the furnace above the hearth 5 it will obviously be readily possible to view the heated portions of the forgings without discomfort.

For a given amount of combustion or fuel supplied the heat concentration can be controlled through controlling the size of the opening 6. It is apparent thatif this opening is reduced in size the heat will build up in the brick work surrounding the combustion chamber 3, whereas if the opening 6 is made relatively large the heat will escape through this opening and not build up.

If it is desired to get a particular concentration of heat on the end of a part to be forged, and this is particularly desirable when only a relatively low temperature such as is used for heating drill points is desired, an additional amount of brick I5 is brought to the edge of the opening 6. The brick l5 is mounted in a casing 16 and may be held in place by a screw 17.

The opening 12 in the roof is ordinarily adjusted to be slightly larger than the opening 6, so that all of the products of combustion will pass out therethrough and some air will be drawn in from the sides. This prevents the forgings from being heated excessively other than at the point where high temperature is desired.

As the forgings to be used in thefurnace such as the one shown are usually of considerable length, I provide the furnace with lugs 18 to which a pipe frame may be attached to support the outer end of the forg ings.

In operating the furnace the temperature is allowed to build up until the pyrometer shows the maximum temperature desired in the forgings. The opening 6 is then adjusted to a proper size to give the necessary area of heating and the amount of fuel supplied is adjusted so that the heat generated will be sufiicient with the concentration given by the adjustment of the opening 6 to maintain a temperature shown on the pyrometer at the desired point. The material to be treated is then inserted between the brick work 10 and brick work 5 at the point nearest the burner 2. The portion of the work to be treated which is to receive the maximum temperature is put over the opening 6. After the first piece inserted has been heated at this point for a few minutes, it is rolled toward the otherend of the furnace and another piece inserted until the furnace is full. It now contains forgings each one of which is receiving a progressively greater concentration of heat and progressively higher temperature than the following one.

In each case the forging will extract heat from the lar 'ge accumulation in the brick work so that it will come up very quickly to the particular temperature at the point of the furnace where it is left, but if the operator for some reason does not withdraw the/forging which has been fully heated, it cannot be overheated, due to the fact that the heat concentrations are always under control.

By thus co-ordinating the parts of the furnace it is possible to heat the forgings rapidly to the desired temperature without using any temperature above that desired, and with the result that the furnace will give large production, but the risk of spoiling forgings through lack of experience on the part of the operator reduced to a minimum.

What I claim is:

1.. In a forging furnace, a combustion chamber provided with a movable hearth above the combustion chamber, and with an adjustable longitudinal opening therein for the escape of the products of combustion.

2. In a forging furnace, a combustion chamber, a movable hearth above the combustion chamber having an adjustable longitudinal opening therein for the escape of the products of combustion, openings along the side of the furnace above the hearth, and a roof for the hearth provided with a longitudinal opening above the said adjustable longitudinal opening for the movable hearth.

3. In a forgingfurnace, a combustion chamber, a movable hearth above the combustion chamber having an adjustable lon gitudinal opening therein for the escape of the products of combustion, openings along the side of the furnace above the hearth, and a roof for the hearth provided with an ad justable longitudinal opening above the said adjustable longitudinal opening of the movable hearth.

4. In aforging furnace, a combustion chamber, a hearth above the combustion chamber-with a longitudinal opening therein for the escape of the products of combustion, a burner connected with said combustion chamber adapted to generate different degrees of heat at different points along said longitudinal opening, and an aperture at the side of said hearth for the insertion of forgings at various points on the hearth transverse of said opening, so as to permit the forgings being inserted at a relatively cool point on the hearth and thereafter moved to the hotter portions, said aperture being so constructed and located as to permit the operator to remove the forgings directly from the hottest portion of the hearth.

5. In a forging furnace, a combustion chamber, a hearth above the combustion chamber with a longitudinal opening therein for the escape of the products of combustion, means for generating different degrees of heat at different points along said longitudinal opening, means for regulating the maximum amount of heat so developed, and means for measuring the temperature at the hottest point in the hearth to the end that such temperature may be maintained at approximately the point to which it is desired to heat the forgings.

6. In a forging furnace at hearth, means for heating the hearth to different temperatures at different points, means for regulating the temperature of the hearth, a temperature measuring device enclosed in a false forging at a relatively hot portion of the hearth, provision for inserting forgings adj acent to such false forging and provision for comparing the color of the forgings with the color of such false forging.

7. In a forging furnace, a combustion chamber, a hearth over the combustion chamher, an opening in the hearth to permit flame to pass upward through the hearth from the combustion chamber, an aperture at the side of the hearth to permit forgings to be placed transverse said opening, a cover for the hearth and an opening in the cover substantially over the opening in the hearth and of sufiiciently greater size than the opening in the hearth so that air will be drawn in through the aperture at'the side of the hearth instead of the products ofcombustion passing out therethrough.

8. In a furnace for heating forgings and the like the combination of a place for initial combustion, a combustion chamber of sufli cient size for combustion to continue and be largely completed therein, said place for initial combustion and said combustion chamber being so related that the temperature will progressively increase from the place of initial combustion to a hottest point, a mass of brick work surrounding such chamber and adapted to absorb heat generated therein, a portion of such brick work serving as a hearth, an aperture in such hearth for direct heat and products of combustion toescape from the combustion chamber, an opening at the side of the hearth through which forgings to be heated may be put into a relatively cool portion of the hearth and moved progressively to a hotter part of the hearth, means for measuring the temperature at the hottest part of the hearth and means for regulating the concentration of heat available at the hearth without changing the amount of combustion.

9. The'method of heating forgings and the like which comprises exposing the part to be heated to the radiant heat ofa mass of brick work and the direct heat of combustion in concentrations, such, that the temperature is below that to which it is desired to heat the part to be forged and progressively eXposingit to increasing concentrations of heat but without exposing it to a concentration of heat substantially in excess of the ultimate temperature desired in the part to be forged.

10. In a forging furnace, means for supporting the work to be heated, means of variable cross sectional area for conductlng the heated gases to'said work, and means for varying the quantity of gases produced.

11. In a forging furnace, means for supand having only line contact with the work.

13. In a forging furnace, a combustion chamber provided with a hearth thereabove, an opening for products of combustion extending through said hearth, and abutment means disposed adjacent one edge of said opening and at an angle to said hearth.

14:. In a forging furnace, a combustion chamber provided with a hearth thereabove, an opening for products of combustion extending through said hearth, abutment means disposed adjacent one edge ofsaid opening and at an. angle to said hearth, and means for changing the position of the abutment means relative to the opening. Y

15. In a forging furnace, a combustion chamber. partially closed "at its top by a hearth provided with a fine extending longitudinally of said combustion chamber, said hearth constituting means for supporting forgings transversely of said flue and along which they. may be moved to vary the heat to which they are exposed.

HARRY o. BREAKER. 

